Catadioptric optical system and exposure apparatus having the same

ABSTRACT

A projection exposure lens system has an object side catadioptric system, an intermediate image and a refractive lens system. The refractive lens system from its intermediate image side and in the direction of its image plane has a first lens group of positive refractive power, a second lens group of negative refractive power, a third lens group of positive refractive power, a fourth lens group of negative refractive power, and a fifth lens group of positive refractive power.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Divisional of U.S. patent application Ser. No. 10/787,809 filed Feb. 25, 2004 (of the same inventors, and now allowed) which is a Continuation of U.S. patent application Ser. No. 10/079,964, now U.S. Pat. No. 6,717,722, filed on Feb. 20, 2002, of the same inventors. The present Divisional Application claims the benefits of U.S. patent application Ser. No. 10/787,809, now allowed, which claims the benefit of Ser. No. 10/079,964 under 35 USC 120. U.S. patent application Ser. No. 10/079,964 is a Divisional Application of U.S. patent application Ser. No. 09/364,382 filed on Jul. 29, 1999 (now U.S. Pat. No. 6,496,306), of the same inventors, which claims benefit of U.S. Provisional Application 60/094,579 under 35 USC 119(e). U.S. Provisional Application 60/094,579 was filed on Jul. 29, 1998.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a projection exposure lens in a projection exposure apparatus such as a wafer scanner or a wafer stepper used to manufacture semiconductor elements or other microstructure devices by photolithography and, more particularly, to a catadioptric projection optical lens with an object side catadioptric system, an intermediate image and a refractive lens system for use in such a projection exposure apparatus.

2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98

U.S. Pat. No. 4,779,966 to Friedman gives an early example of such a lens, however the catadioptric system being arranged on the image side. Its development starting from the principle of a Schupmann achromat is described. It is an issue of this patent to avoid a second lens material, consequently all lenses are of fused silica. Light source is not specified, band width is limited to 1 nm.

U.S. Pat. No. 5,052,763 to Singh (EP 0 475 020) is another example. Here it is relevant that odd aberrations are substantially corrected separately by each subsystem, wherefore it is preferred that the catadioptric system is a 1:1 system and no lens is arranged between the object and the first deflecting mirror. A shell is placed between the first deflecting mirror and the concave mirror in a position more near to the deflecting mirror. All examples provide only fused silica lenses. NA is extended to 0.7 and a 248 nm excimer laser or others are proposed. Line narrowing of the laser is proposed as sufficient to avoid chromatic correction by use of different lens materials.

U.S. Pat. No. 5,691,802 to Takahashi is another example, where a first optical element group having positive refracting power between the first deflecting mirror and the concave mirror is requested. This is to reduce the diameter of the mirror, and therefore this positive lens is located near the first deflecting mirror. All examples show a great number of CaF₂ lenses.

EP 0 736 789 A to Takahashi is an example, where it is requested that between the first deflecting mirror and the concave mirror three lens groups are arranged, with plus minus plus refractive power, also with the aim of reducing the diameter of the concave mirror. Therefore, the first positive lens is located rather near to the first reflecting mirror. Also many CaF₂ lenses are used for achromatization.

DE 197 26 058 A to Omura describes a system where the catadioptric system has a reduction ratio of 0.75</β₁/<0.95 and a certain relation for the geometry of this system is fulfilled as well. Also many CaF₂ lenses are used for achromatization.

For purely refractive lenses of microlithography projection exposure system a lens design where the light beam is twice widened strongly is well know, see e.g. Glatzel, E., Zeiss-Information 26 (1981), No. 92 pages 8-13. A recent example of such a projection lens with +−+−+ lens groups is given in EP 0 770 895 to Matsuzawa and Suenaga.

The refractive partial objectives of the known catadioptric lenses of the generic type of the invention, however show much simpler constructions.

The contents of these documents are incorporated herein by reference. They give background and circumstances of the system according to the invention.

The contents of these documents are incorporated herein by reference. They given background and circumstances of the system according to the invention.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to obtain a catadioptric optical system of new construction principles allowing for large numerical aperture, large image field, sufficient laser bandwidth, solid and stable construction, which takes into account the present limitations on availability of CaF₂ in quantity and quality. This holds for a DUV projection lens and gives the basis for a one material only lens for VUV (157 nm).

In order to achieve the above object, according to the present invention, there is provided a projection exposure lens according to the invention.

Advantageous versions are obtained when including features of the invention.

An advantageous projection exposure apparatus of claim 29 is obtained by incorporating a projection exposure lens according to the invention into a known apparatus.

A method of producing microstructured devices by lithography according to the invention is characterized by the use of a projection exposure apparatus according to the invention.

The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention. Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a view showing the arrangement of an exposure apparatus to which a catadioptric optical system according to the present invention can be applied;

FIG. 2 is a section view of the lens arrangement of a first embodiment;

FIG. 3 is a section view of the lens arrangement of a second embodiment;

FIG. 4 is a section view of the lens arrangement of a third embodiment;

FIG. 5 is a section view of the lens arrangement of a fourth embodiment;

FIG. 6 a is a section view of the lens arrangement of a fifth embodiment;

FIG. 6 b is a representation of an imaging error of the fifth embodiment;

FIG. 7 is a schematic section view of part of the lens arrangement of a sixth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The projection exposure apparatus as schematically shown in FIG. 1 includes an excimer laser light source 1 with an arrangement 11 moderately narrowing bandwidth. An illumination system 2 produces a large field, sharply limited and illuminated very homogeneously, which matches the telecentricity requirements of the projection lens, and with an illumination mode to choice. Such mode may be conventional illumination of variable degree of coherence, annular or quadrupole illumination.

A mask 3 is displaced in the illuminated area by a mask holding and handling system 31, which includes the scanning drive in case of a wafer scanner projection exposure apparatus. Subsequently follows the catadioptric projection exposure lens 4, according to the invention to be described in detail subsequently.

This lens 4 produces a reduced scale image of the mask 3 on a wafer 5. The wafer 5 is held, handled and eventually scanned by unit 51.

All systems are controlled by control unit 6. Such unit and the method of its use is known in the art of microlithographic projection exposure.

However, for exposure of structures in the regime of about 0.2 μm and less resolution at high throughput there is a demand for various projection exposure lenses capable to be operated at 193 nm, eventually also at 248 nm or 157 nm excimer laser wavelengths with reasonably available bandwidths (e.g. 15 pm at 193 nm), at high image side numerical aperature of 0.65 to 0.8 or more with reasonably large rectangular or circular scanning image fields of e.g. 7×20 to 10×30 mm².

Catadioptric systems of the type cited above are in principle suitable for this.

However, according to the invention a number of measures and features have been found to improve these systems.

The example shown in the sectional view of FIG. 2 has the lens data given in Table 1 and makes use only of fused silica lenses. As only one-lens material is used, this design can easily be adapted for other wavelengths as 248 nm or 157 nm.

The intermediate image IMI is freely accessible, so that it is easily possible to insert a field stops. The aperture stop AP is located between lens surfaces 239 and 240 and is also well accessible.

The deflecting mirrors DM1 and DM2 in the catadioptric system CS are defined in their geometry by the demands of separation of the light beams to and from the concave mirror 209 and of clearance from lens 201, 202. It is advantageous that the mirror angle of mirror DM1 differs from 45°, such that the beam deflection angle is greater than 90°. This helps to ascertain large free working distance as well as wide clearance for the light beam relative to the first lens element 201, 202 and also gives full clearance of the lens barrel of the catadioptric systems CS from the object plane 0.

The arrangement of the two deflection mirrors DM1, DM2 allows for a straight optical axis and parallel situation of origin plane 0 and image plane IM, i.e. mask and wafer are parallel and can easily be scanned. However, one of the deflecting mirrors DM1, DM2 can be abandoned or eventually be replaced by a deflecting mirror in the refractive lens RL, e.g. in the air space between lens surfaces 225 and 226. It is also clear the deflecting mirrors can be replaced by other deflecting optical elements (as e.g. the prism in embodiment 6 or others).

A moderate positive lens 201, 202 is placed near the origin plane 0 in the single pass beam area. Its focal length is approximately equal to its distance from the concave mirror 209. This makes that the concave mirror 209 is situated in a pupil plane and thus the diameter required is minimized.

A second positive lens is located in the doubly passed area between the deflecting mirrors DM1, DM2 and the concave mirror 209. As the production conditions of concave mirrors of 200 mm to 300 mm diameter give no strong preference to smaller units—in contrast to lenses, namely such made from CaF₂, where inhomogeneties etc. given strong limitations—there is no need to use this positive lens 203, 204 for reduction of the radius of the concave mirror 209. It is located nearer to the concave mirror 209 than to the first reflection mirror DM1 at a location where it serves best to minimize imaging errors.

The two negative menisci 205, 206; 207, 208 cooperate with the concave mirror 209 in a known manner, giving increased angles of incidence and stronger curvature, thus stronger correcting influence of the concave mirror 209.

It is significant, that the number of lenses in the doubly passed area of the catadoptric system CS is restricted to three, as here every lens counts doubly with respect to system energy transmission and wavefront quality degradation—without giving more degrees of freedom for correction.

Of a total reduction ratio of β=0.25 the catadioptric system CS delivers its part of β_(cs)=1.008.

At the intermediate image plane IMI preferably a field stop FS is inserted, which reduces stray light favorably.

The refractive lens RL following to the intermediate image IMI is of more elaborate design than usual in the art. It is more of a quality as fully refractive projection exposure lenses of recent developments tend to be.

One can see that the five lens group design known from sophisticated refractive microlithography lens designs featuring two waists and three bellies with +−+−+ lens groups in this sequence is adopted. Though the first two bellies (lens surfaces 210 to 219, 224 to 227) are not very strongly expressed, the two waists W1, W2 are significantly established, each by a pair of negative menisci 220, 221; 222, 223 and 228, 229; 230, 231, whose convex surfaces face outwardly.

It is known that these lens groups at the waists W1, W2 as the others can be developed further by incorporating more lenses, e.g. to increase the numerical aperture or the image area.

From another point of view, the refractive lens RL is composed of a field lens group (lens surfaces 210 to 219) of positive power for turning the diverging chief ray into a converging chief ray, an image side positive focusing lens group (lens surfaces 232 to 251), which generates the required large numerical aperture, and intermediately arranged lens elements, which correct imaging errors, especially including sets of oppositely arranged negative menisci (w1, w2).

The −+ power doublets with surfaces 235 to 238 and 239 to 242 are the key to the wide spectral bandwidth at good correction of the chromatic variation in spherical aberration, which is the main residual aberration in these designs. It was found that the alternative arrangement there of +− power doublets gives much worse chromatic variation of spherical aberration. Here a value of 0.35 μm is obtained at 15 pm laser bandwidth.

This example of FIG. 2 is suitable for printing microstructures at a resolution of less than 0.2 μm over an image field of 30×7 mm² rectangle at 6 mm off axis, with an excimer laser source of 0.015 nm bandwidth.

FIG. 3 and Table 2 show a design variant. The catadioptric system CS remains very similar, however its reduction ratio now is less than unity at β_(cs)=0.944.

In the refractive lens the second lens 212, 213 of FIG. 2 is abandoned, while the thick negative lens 245, 246 is split into three units 342, 343; 344, 345; 346, 347.

Also two lenses now are made of CaF₂, namely the elements with the surfaces 342, 343 and 348, 349. Related to the diameter of the greatest lens 330, 331 of ca. 250 mm their diameters of ca. 205 mm and approx. 165 mm are less than 0.81 fold and 0.67 fold. Therefore, their dimension is not too great and effective production is ascertained.

Also they are arranged in the converging light beam in the fifth lens group after the third belly, near the image plane. They help with achromatization. The other features are quite similar as those of the example of FIG. 2, including e.g. the −+ power doublets 332 to 339.

FIG. 4 and table 3 show another example of a catadioptric lens according to the invention.

Now, the catadioptric system CS shows a major revision, as all lenses in the doubly passed region are combined into a single lens group next to the concave mirror 411. It includes the positive lens 403, 404 and three negative lenses 405 to 410. Change from two to three such negative lenses provides smoother increase of beam angles and thus optimizes correction. Thus, the construction of the lens barrel of the catadioptric system CS is simplified. The lenses 403 to 410 and the mirror 411 can be mounted in a compact unit of conventional construction as known from refractive projection exposure lenses. The long distance to the deflecting mirrors DM1, DM2 can be bridged by a thermally stable tubular body, e.g. made of fiber compound, glass ceramics or a bi-metal compound structure.

The positive lens 403, 404 now is made of fluorite (ca. 200 mm dia.), thus helping in achromatization. It is significant for the invention, that at most three to four lenses in total made of a second material are sufficient to provide good achromatization in this basic design.

The reduction ratio of the catadioptric system is β_(cs)=0.931. The refractive lens system is constructed very similar to the one of table 2.

A fourth embodiment is given in FIG. 5 and table 4.

Now the catadioptric system CS again is free of any CaF₂ element. Its principal construction with a compact unit of one positive (503, 504), three negative lenses (505-510) and the concave mirror 511 in one compact unit remains the same as in the third embodiment. The reduction ratio β_(cs) is 0.961 in the most preferred range.

Also the refractive lens RL is of the same overall design as the before mentioned examples. However, the use of CaF₂ lens elements has a novel character. While lens element 544, 545 in a known manner serves for achromatization, the reason for use of CaF₂ in the two lenses 552, 553; 554, 555 next to the image plane IM is another one.

The reason for use of CaF₂ here is the reduction of the “compaction” degradation effect which is rather strong with fused silica lenses at high light intensity and strong asymmetry (caused by narrow scanning image field) at 193 nm wavelength, but far less with CaF₂ lenses (or other crystalline material).

With an overall length—object 0 to image IM—of 1455 mm, a deviation off the axis of the concave mirror 511 of 590 mm, diameter of the concave mirror 511 of 250 mm, greatest lens diameter in the refractive lens system RL of 240 mm (at lens 534, 535) and diameters of the CaF₂ lenses of 195 mm (544, 545), 135 mm (552, 553) and 85 mm (554, 555) the dimensions of this construction are very acceptable. At Lambda=193 nm, 15 pm band width, reduction ratio 0.25, numerical aperture of 0.7, an image field of 26×9 mm² rectangular is imaged at a resolution of better than 0.20 μm.

A fifth embodiment is given in FIG. 6 a and table 5. This is distinguished from embodiment 4 in that only the last two lenses C1, C2 (654, 655; 656, 657) are made of CaF₂ with the aim of reduction of long-time degradation by compaction of fused silica under 193 nm radiation, but no CaF₂ is used for the purpose of achromatization.

The catadioptric system CS consists of a field lens 601, 602 with a focal length f′ related to its distance B to the concave mirror by f′/B=1.004.

Deflecting mirror DM1 deflects the optical axis. Its normal is tilted with respect to the optical axis by 50°. This gives better beam clearance from the field lens 601, 602 than the normal 45°.

The positive lens 603, 604 is combined with three negative lenses 605-610 and the concave mirror 611 into a compact unit. The distance DM1-603 is 432 MM, compared to the distance DM1-611 to the concave mirror of 597 mm; this is 72%.

The reduction ratio of the catadioptric system β_(cs)0.9608 lies in a preferable range near unity, where the achromatizing effect of the concave mirror is best exploited as well as other imaging errors (e.g. curvature of field) are kept small. The positive effect on Petzval sum is very good.

However, the concept of odd aberrations correction (Singh loc. cit.) is not adapted: At the intermediate image plane IMI the values of coma −0.1724—and distortion—−0.0833—by far exceed good correction values, while at the final image plane IM coma (−0.00098) and distortion (−0.000115) are very well corrected, as other typical errors are.

A field stop FS at the intermediate image plane IMI advantageously cuts off disturbing stray light.

According to the invention the catadioptric system is designed with very few elements in compact arrangement for its function is focused on the implementation of the achromatizing and Petzval sum influence of the concave mirror 611.

Detailed correction is the realm of the refractive lens system RL. This is composed of a field lens group FL (surfaces 612 to 621) and a focusing lens group FG (surfaces 634 to 657). Correcting lens elements are inserted in between, including two pairs of opposing negative menisci 622-625 and 630-633. These form two beam waists W1, W2. Thus the +−+−+ five lens group design known from sophisticated refractive projection exposure lenses is established.

The focusing lens group FG hosts the system aperture AP as well as two −+ power lens groups PG1 and PG2 with the above-mentioned advantages.

No achromatizing CaF₂ lens is provided, but as in embodiment 4 the two lenses C1, C2 (654-657) located next the image plane IM are made of CaF₂ for the above mentioned reason of avoidance of compaction.

At a length of 0-IM of 1400 mm and a sideward deviation of 590 mm to the concave mirror 611, the diameter of the concave mirror 611 (and the neighboring lens 609, 610) is limited to 252 mm, while the largest lens 636, 637 of the refractive lens system RL has a diameter of 240 mm and the CaF₂ lenses have only 130 mm (C1) and 85 mm (C2) diameter. Thus requirements of production to avoid extreme diameters are well fulfilled.

FIG. 6 b shows the longitudinal spherical aberration and its chromatic variation at Lambda=193. 30 nm±0.015 nm for this embodiment 5, which as before mentioned is the remnant imaging error limiting the performance of this system.

It can be seen that with a moderately narrowed excimer laser source of Lambda=193.3 nm with 15 pm band width a rectangular field of 26×9 mm can be imaged at a resolution of better than 0.2 μm.

A sixth embodiment is shown in FIG. 7 and table 6. Here, a deflecting prism DP is inserted for deflecting the light path towards the concave mirror 711.

Since the light rays inside the prism DP spread apart less than when they are in air (or nitrogen or helium), the field size can be increased by a certain amount without introducing any vignetting of the light rays by the prism edges. The importance of this design modification increases at higher numerical Aperture. Vignetting of rays limits how large a field size can be handled by the folding elements, and even a relatively small increase in field size is very desirable—for a variety of reasons, including the possibility of shrinking all lens diameters for a given field required. It turns out not to be relevant to try this for the second flat mirror DM2. While FIG. 7 schematically shows the deflecting mirror region, exemplary lens data for a full system are given in table 6. This Prism arrangement can also help to extend the free working distance or to use other mirror angles (e.g. 45°).

Embodiment 7, for which design data are given in table 7, shows the possible extension of the image with side numerical aperture well beyond the 0.7 value of the other examples. The value of NA=0.8 is not yet limiting to this type of lens. The overall construction is as given in the other embodiments, thus no extra drawing is needed for explanation.

Embodiment 8 with lens data of table 8 gives a pure CaF₂ deign for 157 nm wavelength as an example showing the possibilities of the inventive design for use with VUV wavelengths. The overall construction is very much like FIG. 6 a.

Other combinations of claimed features than explicitly described above are within a scope of the invention.

The possibilities of the Schupman achromat for achromatization with only one lens material are fully exploited in embodiments 1 and 8. In consequence, this embodiment 8 presents the first 157 nm design of the Schupman achromat suitable for VUV lithography. Insertion of aspheres and consequent reduction of number and thickness of lenses will further optimize this.

A new aspect of using a second material in a lens for avoiding compaction is given in embodiments 4 to 7.

To simplify achromatization by use of a second material very few elements made from this are sufficient as embodiments 3, 4, 6 and 7 show.

Preferably the lenses between the deflecting elements and the concave mirror are arranged in a compact unit with the latter as in embodiments 3 to 8. All lenses are more distant from the deflecting elements than from the concave mirror, their minimal distances do not exceed their maximum thicknesses (both taken over the diameter), or the length of the compact unit does not exceed its diameter, at least not by more than 50%. The sophisticated design of the refractive lens system as presented allows for good correction at increased image side numerical apertures in the 0.65 to 0.85 range.

While examples are given for the scanning scheme of exposure, the invention as well is useful with step-and-repeat or stitching. Stitching allows for specifically smaller optics. TABLE 1 Lambda = 193.3 nm  β = 0.25  NA = 0.7 No. Radius Thickness Glass  0 Infinity 40.000 201 433.823 20.000 SIO2 202 Infinity 76.000 DM1 Infinity 286.798 Angle 50.5° 203 371.257 25.000 SIO2 204 855.824 216.212 205 −242.813 15.000 SIO2 206 −957.702 29.987 207 −191.563 15.000 SIO2 208 −420.744 12.000 209 267.741 Reflector (203) 281.798 DM2 Infinity 141.534 Angle 39.5° 210 341.605 45.000 SIO2 211 −302.390 0.266 212 −314.725 15.000 SIO2 213 −535.921 21.847 214 −293.712 15.000 SIO2 215 242.074 2.808 216 253.649 50.000 SIO2 217 −418.716 1.000 218 387.621 32.000 SIO2 219 Infinity 23.536 220 338.439 20.000 SIO2 221 −180.073 56.252 222 −200.452 17.000 SIO2 223 −406.872 1.000 224 830.485 35.000 SIO2 225 −406.246 137.396 226 564.466 32.000 SIO2 227 −1292.800 1.000 228 288.764 22.000 SIO2 229 169.297 57.016 230 −189.642 28.572 SIO2 231 −398.135 81.777 232 −476.268 32.000 SIO2 233 −238.618 1.000 234 505.684 17.000 SIO2 235 259.770 13.056 236 455.638 38.000 SIO2 237 −469.418 1.000 238 236.178 15.000 SIO2 239 = AP 145.030 2.543 240 149.636 45.000 SIO2 241 1347.200 1.000 242 138.086 29.000 SIO2 243 273.919 16.837 244 −2450.800 36.643 SIO2 245 114.868 12.598 246 183.269 33.000 SIO2 247 −427.093 0.100 248 119.177 56.567 SIO2 249 352.582 0.100 250 176.817 42.544 SIO2 251 −263.402 15.000 IM Infinity 0.000

TABLE 2 Lambda = 193.3 nm  β = −0.25  NA = 0.7 No. Radius Thickness Glass  0 Infinity 40.000 301 501.959 20.000 SIO2 302 6701.736 83.000 DM1 Infinity Angle 53.00° 303 −477.089 SIO2 304 −5445.982 305 282.396 SIO2 306 1204.642 307 216.126 SIO2 308 519.194 309 298.619 Reflector (303) DM2 Infinity Angle 37.00° 310 −277.399 SIO2 311 876.072 312 384.127 SIO2 313 −245.187 314 −297.630 SIO2 315 778.473 316 −422.020 SIO2 317 945.111 318 −336.194 SIO2 319 −169.717 320 208.247 SIO2 321 414.789 322 −639.842 SIO2 323 420.685 324 −508.419 SIO2 325 1843.176 326 −315.017 SIO2 327 −182.247 328 197.495 SIO2 329 764.726 330 572.623 SIO2 331 246.349 332 −592.087 SIO2 333 −240.082 334 −314.738 SIO2 335 745.437 336 −219.102 SIO2 337 −178.632 338 −269.565 SIO2 339 = AP −8665.509 340 −165.739 SIO2 341 −378.291 342 −5121.046 CAF2 343 457.764 344 511.311 SIO2 345 −143.061 346 −134.125 SIO2 347 −125.446 348 −158.475 CAF2 349 451.948 350 −122.592 SIO2 351 −830.354 352 −374.272 SIO2 353 500.000 IM Infinity

TABLE 3 Lambda = 193.3 nm  β = −0.25  NA = 0.7 No. Radius Thickness Glass  0 Infinity 40.000 401 441.354 20.000 SIO2 402 −3082.575 82.000 DM1 Infinity 404.580 Angle 51° 403 379.755 40.000 CAF2 404 −503.571 10.819 405 −538.291 15.000 SIO2 406 −11216.000 23.000 407 −289.982 15.000 SIO2 408 1481.373 35.434 409 −212.610 15.000 SIO2 410 −422.622 10.747 411 281.484 10.747 Reflector (403) 391.580 DM2 Infinity 95.000 Angle 39° 412 304.777 35.000 SIO2 413 −414.139 36.096 414 −217.633 15.000 SIO2 415 291.419 15.871 416 372.431 48.000 SIO2 417 −351.209 1.000 418 478.050 34.000 SIO2 419 −840.313 52.353 420 336.231 20.000 SIO2 421 175.364 55.562 422 −230.487 17.000 SIO2 423 −430.797 1.000 424 648.294 40.000 SIO2 425 −404.757 99.810 426 527.066 30.000 SIO2 427 −13296.000 1.000 428 288.592 22.000 SIO2 429 167.355 54.577 430 −201.179 20.000 SIO2 431 −801.011 103.872 432 −585.801 36.000 SIO2 433 −252.132 1.000 434 457.102 17.000 SIO2 435 260.610 9.580 436 343.579 43.000 SIO2 437 −739.447 1.000 438 226.319 18.500 SIO2 439 173.228 16.103 440 272.220 34.000 SIO2 441 = AP −7972.902 1.000 442 165.067 34.000 SIO2 443 374.040 12.889 444 2219.918 22.000 CAF2 445 −490.695 0.100 446 −715.705 12.000 SIO2 447 134.285 0.100 448 123.907 36.879 SIO2 449 111.965 9.498 450 147.332 35.000 CAF2 451 −967.651 0.100 452 115.241 69.555 SIO2 453 921.256 0.100 454 294.383 28.447 SIO2 455 −500.000 15.000 IM Infinity

TABLE 4 Lambda = 193.3 nm  β = −0.25  NA = 0.7 No. Radius Thickness Glass  0 Infinity 35.000 501 407.048 16.000 SIO2 502 −85814.000 82.000 DM1 Infinity 431.676 Angle 50° 503 524.134 35.000 SIO2 504 −657.304 8.785 505 −587.479 15.000 SIO2 506 1940.811 25.643 507 −324.153 15.000 SIO2 508 −23676.000 37.709 509 −201.728 15.000 SIO2 510 −422.094 12.854 511 282.375 Reflector (503) 422.676 DM2 Infinity 110.772 Angle 40° 512 373.692 35.000 SIO2 513 −410.297 50.772 514 −222.817 15.000 SIO2 515 317.101 6.370 516 349.335 48.000 SIO2 517 −362.479 1.000 518 729.698 34.000 SIO2 519 −931.019 57.653 520 371.363 20.000 SIO2 521 210.389 53.764 522 −248.647 17.000 SIO2 523 −428.501 1.000 524 937.198 40.000 SIO2 525 −388.007 113.824 526 567.461 30.000 SIO2 527 −4351.070 1.000 528 282.352 22.000 SIO2 529 185.586 56.362 530 −234.431 20.000 SIO2 531 −557.904 132.665 532 −408.165 35.442 SIO2 533 −266.966 1.000 534 404.076 17.000 SIO2 535 238.987 14.763 536 379.049 43.000 SIO2 537 −737.556 1.000 538 245.637 18.500 SIO2 539 178.878 12.206 540 245.508 34.000 SIO2 541 2061.364 10.000 AP Infinity 0.000 542 168.071 34.000 SIO2 543 473.781 9.798 544 1851.461 22.000 CAF2 545 −494.253 0.100 546 −719.297 12.000 SIO2 547 132.814 0.100 548 127.155 34.780 SIO2 549 118.260 11.187 550 169.575 35.000 SIO2 551 −844.545 0.100 552 111.623 74.968 CAF2 553 1756.460 0.100 554 239.829 26.117 CAF2 555 −500.000 15.000 IM Infinity 0.000

TABLE 5 Lambda = 193.3 nm  β = −0.25  NA = 0.7 No. Radius Thickness Glass  0 Infinity 35.000 601 443.397 16.000 SIO2 662 −3263.101 82.000 DM1 Infinity 431.967 Angle 50° 603 510.641 35.000 SIO2 604 −953.685 12.327 605 −534.546 15.000 SIO2 606 1546.359 27.623 607 −295.422 15.000 SIO2 608 −1911.545 32.819 609 −212.072 15.000 SIO2 610 −404.269 12.229 611 279.883 Reflector (603) 422.967 DM2 Infinity 109.448 Angle 40° 612 338.847 28.000 SIO2 613 −769.850 31.900 614 1373.814 18.000 SIO2 615 −915.108 37.909 616 −239.573 15.000 SIO2 617 279.202 6.538 618 301.416 46.477 SIO2 619 −437.969 1.000 620 722.212 30.074 SIO2 621 −1063.807 23.211 622 381.419 19.000 SIO2 623 193.859 52.872 624 −235.061 17.000 SIO2 625 −412.453 1.000 626 990.052 40.000 SIO2 627 −337.530 95.112 628 529.636 30.000 SIO2 629 −0.208 1.000 630 264.737 20.000 SIO2 631 173.477 55.898 632 −213.164 19.000 SIO2 633 −478.343 127.971 634 −384.253 29.998 SIO2 635 −241.972 1.000 636 381.178 17.000 SIO2 637 218.858 11.314 638 296.282 43.000 SIO2 639 −966.118 1.000 640 230.570 18.500 SIO2 641 172.880 14.657 642 271.493 30.000 SIO2 643 −49526.000 4.000 AP Infinity 0.000 644 156.048 36.000 SIO2 645 474.860 12.986 646 −4892.676 20.000 SIO2 647 −452.665 0.100 648 −711.904 34.541 SIO2 649 122.051 9.933 650 171.475 −33.021 SIO2 651 −967.318 0.100 652 112.494 72.297 CAF2 653 3642.643 0.100 654 250.427 26.033 CAF2 655 −500.000 15.000 IM Infinity 0.000

TABLE 6 Lambda = 193.3 nm  β = −0.25  NA = 0.7 No. Radius Thickness Glass  0 Infinity 35.000 701 396.818 16.000 SIO2 702 −4111220.000 1.000 DP Infinity 85.500 SIO2 DP Infinity 435.933 Angle 50° 703 559.897 35.000 SIO2 704 −763.942 2.707 705 −627.112 15.000 SIO2 706 2056.900 24.065 707 −323.749 15.000 SIO2 708 −4114.500 41.268 709 −197.452 15.000 SIO2 710 −416.693 13.024 711 278.696 Reflector (703) 420.933 DM2 Infinity 84.857 Angle 40° 712 391.689 35.000 SIO2 713 −391.139 54.674 714 −217.120 15.000 SIO2 715 328.292 6.584 716 363.974 48.000 SIO2 717 −352.092 11.973 718 753.003 34.000 SIO2 719 −915.634 62.045 720 369.054 20.000 SIO2 721 218.165 56.274 722 −247.872 17.000 SIO2 723 −420.231 1.000 724 970.166 40.000 SIO2 725 −383.655 110.429 726 556.298 30.000 SIO2 727 −5145.200 1.000 728 275.093 22.000 SIO2 729 186.724 57.861 730 −249.939 24.499 SIO2 731 −573.695 138.278 732 −424.514 35.114 SIO2 733 −274.834 1.000 734 391.263 17.000 SIO2 735 226.128 16.728 736 383.272 43.000 SIO2 737 −863.203 1.000 738 239.284 18.500 SIO2 739 178.197 11.299 740 237.727 34.000 SIO2 741 1618.000 10.000 AP Infinity 0.000 742 165.688 34.000 SIO2 743 445.266 9.217 744 1247.900 22.000 CAF2 745 −503.423 0.000 746 −771.731 12.000 SIO2 747 131.678 0.100 748 124.872 29.133 SIO2 749 115.885 13.283 750 179.986 35.000 SIO2 751 −802.711 0.100 752 110.497 77.422 CAF2 753 2393.500 0.100 754 234.953 25.804 CAF2 755 −500.000 15.000 IM Infinity 0.000

TABLE 7 Lambda = 193 nm  β = −0.25  NA = 0.8 No. Radius Thickness Glass  0 Infinity 35.000 801 355.625 15.000 SIO2 802 Infinity 84.000 DM1 Infinity 393.919 Angle 50° 803 621.321 30.000 SIO2 804 17349.000 15.577 805 −522.771 15.000 SIO2 806 7450.061 28.795 807 −279.969 15.000 SIO2 808 −692.552 26.633 809 −231.205 15.000 SIO2 810 −419.760 13.994 811 283.256 Reflector (803) 384.919 DM2 Infinity 103.131 Angle 40° 812 363.520 35.000 SIO2 813 −312.546 19.745 814 −203.460 15.000 SIO2 815 417.901 4.913 816 637.371 44.999 SIO2 817 −299.660 1.000 818 670.513 36.000 SIO2 819 −607.949 99.443 820 409.543 20.000 SIO2 821 184.175 56.726 822 −190.739 18.000 SIO2 823 −300.666 1.000 824 2541.548 35.000 SIO2 825 −423.211 82.343 826 529.976 40.000 SIO2 827 −575.433 1.000 828 338.904 22.000 SIO2 829 161.992 77.036 830 −180.232 20.000 SIO2 831 −286.886 60.230 832 1358.390 50.000 SIO2 833 −310.335 1.000 834 299.546 17.000 SIO2 835 185.330 22.475 836 318.393 15.000 SIO2 837 240.343 11.470 838 351.936 35.000 SIO2 839 −1892.972 1.000 840 241.744 18.500 SIO2 841 201.167 6.992 842 233.761 35.000 SIO2 843 1187.547 0.000 AP Infinity 6.993 844 173.633 65.000 CAF2 845 −647.630 0.100 846 −1026.314 15.000 SIO2 847 134.041 12.672 848 177.508 43.000 SIO2 849 −552.796 0.100 850 111.087 82.051 CAF2 851 366.445 0.100 852 201.556 9.977 CAF2 853 Infinity 15.000 IM Infinity

TABLE 8 Lambda 157.000 nm ± 2 pm  NA = 0.7  β = −0.25 No. Radius Thickness Glass  0 Infinity 35.000 901 509.596 16.000 CAF2 902 −1709.182 82.000 DM1 Infinity 430.770 Angle 50° 903 559.504 35.000 CAF2 904 −1229.460 18.117 905 −727.847 15.000 CAF2 906 1261.260 27.332 907 −297.498 15.000 CAF2 908 −1565.150 32.707 909 −205.835 15.000 CAF2 910 −396.253 12.181 911 279.103 Reflector Φ252 mm (903) 420.578 DM2 Infinity 73.026 Angle 40° IMI Infinity 34.034 912 341.070 28.000 CAF2 913 −1505.473 32.408 914 969.048 18.000 CAF2 915 −805.764 37.523 916 −248.947 15.000 CAF2 917 286.272 5.893 918 307.931 45.973 CAF2 919 −386.903 1.000 920 1003.377 28.290 CAF2 921 −945.839 20.042 922 397.781 19.000 CAF2 923 197.943 53.200 924 −231.060 17.000 CAF2 925 −406.748 1.000 926 878.953 40.000 CAF2 927 −351.000 100.639 928 481.080 30.000 CAF2 929 11551.730 1.000 930 282.768 20.000 CAF2 931 179.880 51.341 932 −217.737 19.000 CAF2 933 −511.417 127.776 934 −377.857 29.786 Φ240 mm CAF2 935 −241.099 1.000 936 377.020 17.000 CAF2 937 218.220 11.262 938 299.020 43.000 CAF2 939 −943.927 1.000 940 228.020 18.500 CAF2 941 168.921 13.866 942 263.149 30.000 CAF2 943 −27570.214 0.752 AP Infinity 8.754 944 157.192 36.000 CAF2 945 476.977 13.281 946 −5291.918 20.000 CAF2 947 −428.700 0.100 948 −634.165 34.624 CAF2 949 123.520 10.454 950 180.781 33.303 CAF2 951 −732.821 0.100 952 115.913 72.125 CAF2 953 3615.409 0.100 954 308.142 25.802 CAF2 955 −500.000 15.000 IM Infinity Refractive Indices CaF₂ Lambda = 157.002 157.000 156.998 n = 1.560047 1.560052 1.560057 

1. (canceled)
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 22. A projection exposure lens system comprising a both side telecentric refractive lens system with a numerical aperture of at least 0.7, with a first lens not immediately next to, but spaced one apart from its image plane and a second lens next to its image plane, said first lens being concave on its image ward surface, said second lens being convex on its surface facing said first lens, said concave surface and said convex surface being substantially concentric.
 23. A system according to claim 22, said first lens being a meniscus lens.
 24. A system according to claim 22, said second lens being a plano-convex lens.
 25. A system according to claim 22, said first lens and said second lens both being of the same material.
 26. A system according to claim 25, said material being CaF₂.
 27. A system according to claim 22, an axial distance between said first and second lens being of the order of magnitude of one millimeter.
 28. A system according to claim 22, a difference of ratio of said concave and said convex surface being of the order of magnitude of one millimeter.
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